Malcolm Turnbull will become Australia's 29th prime minister after ousting Tony Abbott in a party room ballot in Canberra tonight.  

After a tense 30-minute wait, Chief Government Whip Scott Buchholz emerged from the meeting to announce Turnbull had won the vote 54-44.

"Tonight there were two ballots conducted; one ballot for leader, one ballot for deputy leader," Buchholz said. 

"Malcolm Turnbull was successful on 54, Tony Abbott on 44 and one was informal."

Julie Bishop was reelected as deputy Liberal leader, defeating Kevin Andrews 70 votes to 30. 

The meeting was called after Turnbull approached Mr Abbott after question time today to request a leadership ballot.

(9news)